Hydrangea plant named ‘H218916’

ABSTRACT

A new and distinct cultivar of  Hydrangea  plant named ‘H218916’, characterized by its upright and uniformly mounded plant habit; vigorous growth habit and rapid growth rate; freely branching habit with strong, thick and sturdy stems; freely and uniformly flowering habit; mophead-type inflorescences with numerous cupped white-colored sterile flowers with sepals that are undulate; and good postproduction longevity.

Botanical designation: Hydrangea macrophylla.

Cultivar denomination: ‘H218916’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Hydrangea plant, botanically known as Hydrangea macrophylla, commercially referred to as a mophead-type Hydrangea and hereinafter referred to by the name ‘H218916’.

The new Hydrangea plant is a product of a planned breeding program conducted by the Inventor in De Kwakel, The Netherlands and Lengerich, Germany. The objective of the breeding program was to create new strong and freely-branching Hydrangea plants with strong sturdy stems, uniform flowering habit, large inflorescences with numerous showy sterile flowers, attractive sterile flower color and good postproduction longevity.

The new Hydrangea plant originated from a cross-pollination made by the Inventor in March, 2013 in De Kwakel, The Netherlands, of a proprietary selection of Hydrangea macrophylla identified as code number 06-0101-127, not patented, as the female, or seed, parent with a proprietary selection of Hydrangea macrophylla identified as code number 09-0212-001, not patented, as the male, or pollen, parent. The new Hydrangea plant was discovered and selected by the Inventor as a single flowering plant from within the progeny of the stated cross-pollination in a controlled greenhouse environment in Lengerich, Germany in March, 2014.

Asexual reproduction of the new Hydrangea plant by vegetative tip cuttings in a controlled environment in De Kwakel, The Netherlands since April, 2015 has shown that the unique features of this new Hydrangea plant are stable and reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

Plants of the new Hydrangea have not been observed under all possible combinations of environmental conditions and cultural practices. The phenotype may vary somewhat with variations in environmental conditions such as temperature and light intensity without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined to be the unique characteristics of ‘H218916’. These characteristics in combination distinguish ‘H218916’ as a new and distinct Hydrangea plant:

-   -   1. Upright and uniformly mounded plant habit.     -   2. Vigorous growth habit and rapid growth rate.     -   3. Freely branching habit with strong, thick and sturdy stems.     -   4. Freely and uniformly flowering habit.     -   5. Mophead-type inflorescences with numerous cupped         white-colored sterile flowers with sepals that are undulate.     -   6. Good postproduction longevity.

Plants of the new Hydrangea can be compared to plants of the female parent selection. Plants of the new Hydrangea differ primarily from plants of the female parent selection in sterile flower sepals as plants of the new Hydrangea have sterile flower sepals with crenate to serrate margins whereas plants of the female parent selection have sterile flower sepals with entire margins.

Plants of the new Hydrangea can be compared to plants of the male parent selection. Plants of the new Hydrangea differ primarily from plants of the male parent selection in inflorescence form as plants of the new Hydrangea have mophead-type inflorescences whereas plants of the male parent selection have lacecap-type inflorescences.

Plants of the new Hydrangea can be compared to plants of the Hydrangea macrophylla ‘HBA215909’, disclosed in U.S. Plant Pat. No. 29,172. In side-by-side comparisons, plants of the new Hydrangea differ primarily from plants of ‘HBA215909’ in the following characteristics:

-   -   1. Plants of the new Hydrangea have shorter internodes than         plants of ‘HBA215909’.     -   2. Plants of the new Hydrangea have firmer panicles than plants         of ‘HBA215909’.     -   3. Plants of the new Hydrangea have more sterile flowers per         inflorescence than plants of ‘HBA215909’.     -   4. Sterile flowers of plants of the new Hydrangea are cupped         whereas sterile flowers of plants of ‘HBA215909’ are flat.     -   5. Sterile flowers of plants of the new Hydrangea have serrate         to crenate margins whereas sterile flowers of plants of         ‘HBA215909’ have entire to slightly crenate margins.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying colored photographs illustrate the unique appearance of the new Hydrangea plant showing the colors as true as it is reasonably possible to obtain in colored reproductions of this type. Colors in the photographs may differ from the color values cited in the detailed botanical description which accurately describe the colors of the new Hydrangea plant.

The photograph on the first sheet is a side perspective view of a typical flowering plant of ‘H218916’.

The photograph on the second sheet is a close-up view of a typical inflorescence of ‘H218916’.

DETAILED BOTANICAL DESCRIPTION

Plants used in the aforementioned photographs and in the following description were grown during the late spring and early summer in 13-cm containers in a glass-covered greenhouse in De Kwakel, The Netherlands and under cultural practices typical of commercial Hydrangea production. During the production of the plants, day and night temperatures averaged 17° C. Plants of the new Hydrangea were one year old when the photographs and description were taken. Plants of the new Hydrangea can be successfully treated with aluminum sulfate to “blue” the inflorescences. In the following description, color references are made to The Royal Horticultural Society Colour Chart, 2015 Edition, except where general terms of ordinary dictionary significance are used.

-   Botanical description: Hydrangea macrophylla ‘H218916’. -   Parentage:     -   -   Female, or seed, parent.—Proprietary selection of Hydrangea             macrophylla identified as code number 06-0101-127, not             patented.         -   Male, or pollen, parent.—Proprietary selection of Hydrangea             macrophylla identified as code number 09-0212-001, not             patented. -   Propagation:     -   -   Type cutting.—By vegetative tip cuttings.         -   Time to initiate roots, summer.—About two weeks at             temperatures about 23° C.         -   Time to initiate roots, winter.—About 18 days at             temperatures about 20° C.         -   Time to produce a rooted young plant, summer.—About four             weeks at temperatures about 23° C.         -   Time to produce a rooted young plant, winter.—About five             weeks at temperatures about 20° C.         -   Root description.—Thick; typically whitish brown in color,             actual color of the roots is dependent on substrate             composition, water quality, fertilizer type and formulation,             substrate temperature and physiological age of roots.         -   Rooting habit.—Freely branching; dense. -   Plant description:     -   -   Plant and growth habit.—Upright and uniformly mounded plant             habit; strong and sturdy stems; rapid growth rate and             vigorous growth habit.         -   Plant height.—About 25 cm to 30 cm.         -   Plant diameter or area of spread.—About 50 cm to 60 cm. -   Lateral branch description:     -   -   Branching habit.—Freely branching habit; when pinched, about             ten lateral branches develop per plant.         -   Length.—About 18 cm to 23 cm.         -   Diameter.—About 6 mm.         -   Internode length.—About 3.5 cm to 4 cm.         -   Texture.—Smooth, glabrous; fully developed, woody.         -   Aspect.—Upright to about 20° from vertical.         -   Strength.—Strong, sturdy.         -   Color.—When developing: Close to 144B; at internodes, close             to 187A; lenticels, close to 187A. Developed: Close to 144B;             at the internodes, close to 187A; when woody, close to 177D;             lenticels, close to 187A. -   Leaf description:     -   -   Arrangement.—Opposite, simple.         -   Length.—About 10 cm to 14 cm.         -   Width.—About 7 cm to 8 cm.         -   Shape.—Ovate.         -   Apex.—Aristate to cuspidate.         -   Base.—Obtuse.         -   Margin.—Dentate to serrate.         -   Texture, upper surface.—Smooth, glabrous.         -   Texture, lower surface.—Rugose, glabrous.         -   Venation pattern.—Pinnate.         -   Color.—Developing and fully expanded leaves, upper surface:             Close to 147A; venation, close to 145B. Developing and fully             expanded leaves, lower surface: Close to 137C; venation,             close to 145D.         -   Petioles.—Length: About 2 cm to 3.5 cm. Diameter: About 3 mm             to 4 mm. Texture, upper and lower surfaces: Smooth,             glabrous. Color, upper and lower surfaces: Close to 145B. -   Flower description:     -   -   Flower type and habit.—Showy sterile flowers and small             inconspicuous fertile flowers arranged on mophead-type             terminal panicles; panicles globular in shape; flowers face             upright to outwardly depending on their position in the             inflorescence.         -   Fragrance.—None detected.         -   Natural flowering season.—Plants begin flowering about one             year after planting; flowering begins in the early summer             and is continuous throughout the summer in Northern Europe.         -   Flower longevity.—Fertile flowers last about one month on             the plant, fertile flowers not persistent; sterile flowers             last about four months on the plant, sterile flowers             persistent.         -   Quantity of flowers.—Freely flowering habit; about 30             fertile flowers per panicle and about 130 to 140 sterile             flowers per panicle.         -   Panicle height.—About 8 cm to 10 cm.         -   Panicle diameter.—About 14 cm to 18 cm.         -   Fertile flower buds.—Length: About 3 mm. Diameter: About             3 mm. Shape: Spherical. Color: Close to 145A.         -   Sterile flower buds.—Length: About 3 mm. Diameter: About             3 mm. Shape: Spherical. Color: Close to 155A.         -   Fertile flower diameter.—About 5 mm.         -   Fertile flower depth (height).—About 5 mm.         -   Sterile flower diameter.—About 2.5 cm to 3 cm.         -   Sterile flower depth (height).—About 1 cm.         -   Petals, fertile flowers.—Quantity and arrangement: Five in a             single whorl. Length: About 3 mm. Width: About 2 mm. Shape:             Ovate. Apex: Acute. Base: Attenuate. Margin: Entire.             Texture, upper and lower surfaces: Smooth, glabrous. Color:             When opening, upper and lower surfaces: Close to 145D. Fully             opened, upper and lower surfaces: Close to 155D; color does             not change with development.         -   Petals, sterile flowers.—Quantity and arrangement: Four in a             single whorl. Length: About 3 mm. Width: About 2 mm. Shape:             Rounded. Apex: Acute. Base: Obtuse. Margin: Entire. Texture,             upper and lower surfaces: Smooth, glabrous. Color: When             opening, upper and lower surfaces: Close to NN155B. Fully             opened, upper and lower surfaces: Close to NN155B; color             does not change with development.         -   Sepals, fertile flowers.—Quantity and arrangement: Five in a             single whorl. Length: About 3 mm. Width: About 1.5 mm to             2 mm. Shape: Ovate. Apex: Acute. Base: Obtuse. Margin:             Entire. Texture, upper and lower surfaces: Smooth, glabrous.             Color: When opening, upper and lower surfaces: Close to             145B. Fully opened, upper and lower surfaces: Close to 145B;             color does not change with development.         -   Sepals, sterile flowers.—Quantity and arrangement: Four in a             single whorl. Length: About 1.5 cm to 2.5 cm. Width: About             2.5 cm to 3 cm. Shape: Deltoid; undulate and cupped. Apex:             Obtuse. Base: Obtuse. Margin: Crenate to serrate. Texture,             upper and lower surfaces: Smooth, glabrous. Color: When             opening, upper and lower surfaces: Close to 145C. Fully             opened, upper surface: Close to NN155C; with development,             color becoming closer to 145C; no significant color change             occurs when plants are “blued”, that is, treated with             aluminum sulfate. Fully opened, lower surface: Close to             NN155C; with development, color becoming closer to 145D.         -   Pedicels, fertile flowers.—Length: About 8 mm. Diameter:             About 2 mm to 3 mm. Strength: Strong. Aspect: Mostly             upright. Texture: Smooth, glabrous. Color: Close to 157B.         -   Pedicels, sterile flowers.—Length: About 2 cm to 2.5 cm.             Diameter: About 2 mm. Strength: Strong. Aspect: Erect to             about 45° from vertical. Texture: Smooth, glabrous. Color:             Close to NN155B.         -   Reproductive organs, fertile flowers.—Stamens: Quantity per             flower: Eight. Filament length: About 1 mm. Filament color:             Close to 155D. Anther length: About 1 mm. Anther shape:             Conical. Anther color: Close to 155B. Pollen amount:             Abundant. Pollen color: Close to 155D. Pistils: Pistil             quantity per flower: Three. Pistil length: About 3 mm.             Stigma shape: Oval. Stigma color: Close to 150D. Style             length: About 2 mm to 3 mm. Style color: Close to 155B.             Ovary color: Close to 155B.         -   Reproductive organs, sterile flowers.—To date, reproductive             organ development has not been observed on sterile flowers             of plants of the new Hydrangea.         -   Seeds, only produced by fertile flowers.—Quantity per             fertile flower: About 20 to 30. Length: About 0.5 mm.             Diameter: About 0.2 mm. Color: Close to 200C. -   Pathogen & pest resistance: Under commercial production conditions,     plants of the new Hydrangea have not been observed to be resistant     to pathogens and pests common to Hydrangea plants to date. -   Temperature tolerance: Plants of the new Hydrangea have been shown     to be tolerant to temperatures ranging from about 3° C. to about 38°     C. 

It is claimed:
 1. A new and distinct Hydrangea plant named ‘H218916’ as illustrated and described. 